The present invention relates to wheelchair lifts and, in particular, to wheelchair lift apparatus for providing access from a landing to a vehicle.
In recent years, increasing sensitivity to the need to provide for the mobility of handicapped persons has resulted in a proliferation of lift devices for handicapped persons. One type of lift device enabling a handicapped person to use transit facilities is fixed to the landing and includes, as part of a lifting platform, an extendable bridge for providing access from the lifting platform laterally across the threshold to a light rail vehicle. Illustrative of such devices are German Patent No. P3325036.7, dated July 11, 1983; Williams, U.S. Pat. No. 5,576,539, dated Mar. 18, 1986; and Hussey, U.S Pat. No. 4,499 issued Feb. 19, 1985. In such lift devices, the bridge is interconnected to the platform rather than being independently mounted on a separate support structure. Also, such lifts require considerable space on the landing and hence creates a substantial obstruction to the free flow of non handicapped traffic around the lift device.
In order to overcome the obstruction problem which such lifts present, various mobile lifts have been devised which can be moved so they do not obstruct, For example, United Kingdom Patent No. 2,055,344 to Andersson illustrates a mobile lift which must be attached to the vehicle so as to provide the support necessary for the platform as it is being raised. Also, the bridge portion is hinged to the platform and hence raises and lowers with the platform. Kingston U.S. Pat. No. 4,564,096, dated Jan. 14, 1986 similarly shows a movable (transportable) lift which requires mounting or attachment to the rail vehicle to provide the necessary stability lost because of the mobility feature. The necessity to attach the lift to the rail vehicle greatly increases the time necessary to prepare the lift for use and poses significant risks of collapse if the attachment is done incorrectly.
O'Brian et al, U.S. Pat. No. 3,888,463, dated June 10, 1975 illustrates another wheelchair lift which is movable into a position extending at least part way under the vehicle thereby eliminating the need to attach the lift to the rail vehicle. Also, the platform has no bridge member but rather abuts directly against the threshold of the vehicle. Obviously, such an arrangement is not adaptable to a rail vehicle which also has steps. Finally, King Canadian Patent No. 1095462, issued Feb. 10, 1981, shows an apparatus for transferring wheelchair confined passengers between an aircraft and an aircraft tarmac. However, King discloses a bridge member which is necessarily attached to and moves with the platform as it is raised and lowered. Also, King does not provide a support structure as in the present invention.